The Adventure of the Grey Messenger
by JolieBlack
Summary: A mysterious masked messenger appears at the door of 221 Baker Street, bearing a strange gift for the world's only consulting detective. Shortly afterwards, a series of seemingly unconnected tragedies rocks London, setting Sherlock and John off on a thrilling adventure filled with murder, mystery, and music. Casefic. Gen. 100 % canon-compliant!
1. Chapter 1

**Author's Note:**

I co-wrote this story with my partner in crime, the brilliant RubraSaetaFictor, and we've just begun to post it on AO3 together. Since Rubra isn't here on the site, she's graciously allowed me to post it under my name here.

I'm afraid this is only a slightly pared-down version of the story as it will appear on AO3, because over there, it has a multi-media aspect as well as an interactive aspect, both of which this site doesn't support.

But I still hope to take you all on a solid and exciting adventure, even so!

The story is set between "The Empty Hearse" and "The Sign of Three".

It's not a WIP, but as good as complete, apart from some minor final edits, so there's no danger of it being abandoned.

We treasure all feedback!

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 **INT. - 221B Baker Street, London – The Sitting Room - DUSK**

 **Wednesday, 5 March 2014**

 _It's an early evening in March. The sitting room at 221B Baker Street is cosily lit only by reading lamps. Muted traffic noise comes up from the street below, but there is little to disturb the quiet domesticity of the scene. John, in one of his comfortable jumpers and with his legs up, is in his armchair, absorbed in a paperback. Sherlock, in his usual suit but sans jacket, is sitting at the kitchen table, lighting a piece of fabric on fire briefly over a Bunsen burner, before blowing it out and sniffing it. Then he puts it down and picks up another, setting it alight, too. After a moment, John lets his book sink down._

JOHN: Alright, it was odd enough when it smelled like celery, and I said nothing about vinegar, either, but now it smells like you're burning sheep!

SHERLOCK _(barely looking up from the charred bit of fabric in his hand):_ Very good, John, that was wool suiting. Burns briefly, then chars to an irregular dark ash and smells of - ( _sniffing at the burned scrap)_ \- burning hair, only less acrid.

JOHN _(turning around in his seat):_ And the celery?

SHERLOCK: Nylon. Melts into a hard grey bead.

JOHN: Why are you burning fabric?

SHERLOCK _(setting another scrap on fire):_ It's Ash Wednesday.

JOHN _(drily):_ Right, of course. _(He covers his noise with his hand_. _)_ Oh hell, put that out. It smells like burning tyres.

SHERLOCK _(coughing slightly):_ Olefin. Commonly found in carpeting and vehicle interiors.

John gets up, walks over to the left hand window and pushes it half-way up.

JOHN: Why again are you doing this?

SHERLOCK: I told you, it's Ash Wednesday. I find the name serves excellently as a reminder to annually update my collection. _(He turns the small singed scrap of fabric in his fingers.)_ Traditionally, I would do burn tests of new tobacco products for my monograph. But when you invited yourself over, I felt you might not approve, ergo, textile burn testing today.

JOHN: An evening of inhaling nicotine would've been healthier than this. _(He returns to his chair and stands by it, facing the kitchen.)_ Do you really have to burn things, Sherlock? Come on, just -

John gestures to Sherlock's chair. Sherlock looks down at the fabric in his hand, and drops it into a jar. He stands up, walks over to his chair and sits down somewhat stiffly.

SHERLOCK: Okay. _(There is an awkward silence for a moment. Then Sherlock nods at the paperback in John's hand_. _)_ How's your book?

JOHN: Really good.

SHERLOCK: Good. _(He pauses, clearly waiting for John to say more_. _)_ Well, that was enlightening.

JOHN: It's about Napoleon. _(He holds it up so Sherlock can see the title, which features a reproduction of a portrait painting of the French emperor_. _)_ I think you'd like it.

SHERLOCK: Who?

JOHN: Napoleon? One of the greatest military commanders in history?

SHERLOCK: And this would interest me why?

JOHN: Well, there's a really clever chapter examining all the variables of the Battle of Waterloo and how it shifted the outcome. Like, for example, a tiny shift of the weather could have changed the whole course of European history. If it wasn't for the rain, we could all be speaking French now.

SHERLOCK _(deadpan):_ I can barely imagine a more terrible hardship. _(Dismissively)_ And in any case, third-rate speculative history is not my department, and I wouldn't have thought _you_ -

JOHN _(sarcastically):_ Well, what a pleasant interlocutor you make. _(He flips the book around to read from the blurb.)_ "Universally acclaimed to be the best biography of Napoleon Buonaparte ever written." The Times Literary Supplement. _(He glances up pointedly at his friend for moment, then scans the back of the book for more ammunition_. _)_ Professor Ernest P. Walker, PhD. Holds a chair in European History at Oxford. Member of the British Academy. Writes for the Encyclopaedia Britannica. That's good enough for me, I think.

SHERLOCK _(airily):_ Well, I suppose when it comes to overwritten prose, you are the expert.

JOHN _(narrowing his eyes):_ Remind me to never try to chat with you again.

He makes a move to flick his book open again where he's marked the page. But his gaze comes to rest on the title picture instead. After a minute or so of silence, while John seems to be quite lost in thought -

SHERLOCK _(under his breath):_ "The young Alexander conquered India. Was he alone?"

JOHN _(looking up):_ What?

SHERLOCK: "Caesar beat the Gauls. Did he not have even a cook with him?"

JOHN _(with a frown):_ Are you getting hungry now?

SHERLOCK: No. It's what _you_ were thinking. "Who built Thebes of the seven gates? In the books you will find the name of kings. Did the kings haul up the lumps of rock?" You're not the first to wonder, you know, how strange it is that of several billion people on this planet at any one time, one man goes down in history and all the others don't. Or _isn't_ that what you were thinking?

JOHN: Well... yes. Sort of. _(He puts the book down on the small table next to his chair_. _)_ I was thinking about Waterloo, actually, and how Napoleon was brought down. Individually, none of his opponents were in his league, or even close. But together, they did it.

SHERLOCK: I thought it was the rain.

JOHN: That, too.

SHERLOCK _(with a smirk):_ So, are you arguing that ten idiots make one genius?

JOHN _(with a snort):_ You'd hate that idea, wouldn't you?

SHERLOCK _(dismissively):_ I would if it were true.

Downstairs, the doorbell rings, but neither of them reacts.

A moment later, the front door opens, then closes again, and through the open window, they can hear a car driving away. There are steps on the stairs, and Mrs Hudson enters by the open sitting room door.

MRS HUDSON: Woo-hoo! _(She shudders in the draught from the window.)_ Oh. Don't you find it a bit draughty in here? _(She advances to Sherlock's chair, a plain white envelope_ _in her hand.)_ Someone's just brought this for you, Sherlock.

SHERLOCK _(holding out his hand without looking either at her or at the envelope):_ Who was it?

MRS HUDSON: I couldn't tell.

She puts the envelope in his hand, then walks on to the open window behind Sherlock's chair to close it.

SHERLOCK _(over his should_ er _):_ Didn't they say?

MRS HUDSON: No, he didn't give his name. He seemed in rather a hurry.

SHERLOCK: "He?" What did "He" look like?

MRS HUDSON: I don't know.

 _Sherlock and John exchange a look, confused. Mrs Hudson closes the window, then turns back towards the room._

MRS HUDSON: He was wearing a mask.

SHERLOCK & JOHN _(simultaneously):_ WHAT?

 _Sherlock jumps up from his chair, rushes to the window and pushes it right back up to lean out and look. John, however, makes a bee-line for the open door and races down the stairs. After a moment, Sherlock runs after him and Mrs Hudson runs after Sherlock._

* * *

 **INT. - 221B Baker Street – The Hall – DUSK**

 _In the downstairs hall, John is already coming back inside from the street as Sherlock comes thundering down the stairs, two at a time, Mrs Hudson following. John closes the door behind him and shakes his head, too out of breath to speak._

SHERLOCK: Gone?

JOHN: No sign of him. Must have left in a car.

SHERLOCK _(turning to confront his landlady):_ Mrs Hudson. What in the world possessed you to let a masked stranger into the house?

MRS HUDSON _(rather flustered):_ He never passed the threshold! He just handed me the envelope, said "For Mr Sherlock Holmes. Please let him have it immediately." and then left again. Very polite, very civilised. _(To Sherlock, reproachfully)_ We've had dodgier visitors here, young man, and none of them mine.

 _Sherlock thrusts the envelope at John and takes Mrs Hudson by the shoulders, not ungently, but still quivering with urgency._

SHERLOCK: What did he look like? The mask? The clothes?

MRS HUDSON _(screwing up her face in concentration, trying to remember):_ Very old fashioned – a long wide cloak, black or dark grey. And a three-cornered hat, like a pirate. The mask was plain black, and left only the eyes free.

 _S_ _herlock huffs a frustrated breath. John, meanwhile, has opened the envelope. He retrieves two slips of paper from it._

JOHN _(with a frown):_ Concert tickets. For the Academy of St. Martin in the Fields. They're playing –

 _Sherlock holds up a hand to stop him. All the tension is suddenly gone from his expression. Instead, a grin is spreading across his face._

SHERLOCK: - Mozart's Requiem. _(He starts to laugh_. _)_ Oh, Mycroft. That really wasn't necessary.

JOHN: What? You mean they're from Mycroft?

SHERLOCK _(still very much amused):_ Of course. It's exactly his sense of humour.

JOHN _(puzzled):_ I didn't know he _had_ a sense of humour.

SHERLOCK _(straight-faced for a moment):_ Why else do you think he insisted on kidnapping you with such regularity?

JOHN _(rolling his eyes):_ Seriously. Isn't a masked messenger a little over the top, even for Mycroft?

MRS HUDSON _(with decision):_ I know Mycroft's voice, and that wasn't him.

SHERLOCK: No, of course it wasn't him personally. He's not in town. He's in Zurich, getting shouted at.

 _Mrs Hudson and John gape at him._

SHERLOCK _(patiently):_ That's why _I'm_ getting his tickets. Not for the first time. He's got a subscription for the Academy's London concerts, but he rarely has the time to go.

 _He takes the tickets from John and glances over them._

SHERLOCK: Well, John, better run home and put on something decent. It's at eight tonight.

JOHN: What? Me, too?

SHERLOCK: There are two tickets, aren't there? And Mary's away, anyway.

MRS HUDSON _(to John, in a tone of polite enquiry):_ Oh, is she, John?

SHERLOCK _(curtly):_ She's in Birmingham, getting drunk.

 _He clicks the final "k". Mrs Hudson looks mildly disconcerted. John shoots Sherlock a dirty look, then hurries to explain things to Mrs Hudson._

JOHN: Someone's hen night. Old friend of hers, from her nursing school days, I think.

 _(To Sherlock, nodding at the concert tickets)_ You know, I don't think I'm exactly -

SHERLOCK _(sarcastically):_ Oh yes, sorry. It's only the Academy of St. Martin in the Fields, not the Fifth Northumberland Fusiliers Marching Band.

 _John looks seriously offended._

MRS HUDSON _(in a disapproving tone):_ Boys.


	2. Chapter 2

**INT. – The church of St. Martin-in-the-Fields, Trafalgar Square, London - NIGHT**

 **Wednesday, 5 March 2014**

 _John and Sherlock are in their places in the church of St. Martin-in-the-Fields, which is packed to the last seat, ready for the concert to begin. Their seats are right in the front row, towards one end. Sherlock is in his customary dark suit, and John, as instructed, has also dressed with particular care. He is wearing his black engagement suit, but with a slightly more cheerful tie this time. John is reading in the programme brochure, slowly turning pages. Sherlock keeps looking over his shoulder, his eyes darting all over the church. All of a sudden, the phone in John's pocket pings a text alert. Sherlock turns back to his friend and raises a disapproving eyebrow. John fumbles to get his phone out, visibly embarrassed that he forgot to switch it off. He glances at the screen while putting it on silence. A fond little smile lights up his face._

SHERLOCK: Still coherent, is she?

JOHN _(pointedly):_ Stone cold sober, at least by her spelling.

SHERLOCK: Well, the night's still young.

 _He resumes his scrutiny of the concert venue, now focussing unobtrusively on the people sitting immediately next to him._

JOHN _(his eyes back on the concert programme):_ Stop deducing your neighbours, Sherlock. _(Sherlock doesn't react_. _)_ By the way – _(John looks up again_. _)_ \- why's Mycroft getting shouted at in Zurich?

SHERLOCK: What? Oh, I don't know. Something to do with a bank. They've been negotiating back and forth for months, and their director, who is a textbook choleric, is getting louder every time they meet, and less and less imaginative in his expletives.

JOHN: Why would Mycroft bother talking to a Swiss bank in person? Seems a bit out of his domain.

SHERLOCK: If you asked Mycroft, he'd insist that everything is his domain. But he mentioned HM Revenue and Customs, so at that point I decided that my attention was better served determining how fast I would have to stir my cup of tea for the kinetic energy from my spoon to make the fluid hotter rather than cooler.

JOHN: Does he do that often? Go abroad and sort things out for government agenücies, I mean?

SHERLOCK: Oh yes. He juggles three dozen aliases for that sort of thing. Can't wait to find out what Anthea came up for him on this occasion.

JOHN _(with a smirk):_ Mr Moneypenny?

SHERLOCK: Probably.

JOHN: Are you telling me _she's_ got a sense of humour, too?

SHERLOCK _(with a smile):_ You'd be surprised. But yeah, Mycroft and legwork. He hates it, of course. You should hear how he moans, every time he has to go on one of those trips. Of course, he believes that the world will stop turning if he leaves his London office for more than a day. But lo and behold, he can go away for a whole week and let himself be shouted at from Brussels to Baghdad - Earth's rotation remains unaffected, much to his chagrin.

JOHN _(resuming his reading):_ Well, in case that Swiss banker needs some inspiration for more creative maledictions, this Requiem is full of it. "Burned up by eternal fire"... "sentenced to acrid flames"... real cheery.

 _At that moment, applause rises from the ranks of the audience as the members of the orchestra and the choir enter to take their places on the stage. Shortly afterwards, the solemn, measured music of the opening movement of Mozart's Requiem is filling the church._

* * *

 **EXT. - Trafalgar Square, outside St. Martin-in-the-Fields – NIGHT**

 _After the concert, Sherlock and John, back in their overcoats, come out of the church and walk down the steps. Before them opens the huge expanse of the brightly lit and still quite busy Trafalgar Square._

SHERLOCK: So, how did you like it?

JOHN: Hmm. Heavy artillery. But, yeah. Impressive. That music makes you feel rather small and … mortal, somehow. If you know what I mean.

SHERLOCK _(soberly):_ Oh, I do. Small and _stupid._ _(John frowns, but before he can comment, Sherlock continues in a much lighter tone_. _)_ So, dinner now?

JOHN: Yeah, sure. Is it on Mycroft, too?

SHERLOCK: I'm sure we can find a way.

 _They turn left along Charing Cross Road, but they've only got a few steps further when the phone in Sherlock's pocket rings. He takes the call while they walk on._

SHERLOCK _(into the phone):_ Yes? … Ah. Yes. _(He halts_. _)_ … Alright. Where? … Good. We're on our way. _(He ends the call and turns to John. His face has lit up with anticipation.)_ Lestrade.

JOHN: Anyone dead?

SHERLOCK: Arson.

JOHN _(drily):_ How fitting.

 _Sherlock pockets his phone, steps up to the kerb and flags down a cab. Clearly, the game is on._

* * *

 **EXT. - Residential Street, West Hampstead, London - NIGHT**

 _A residential street in a fairly well-off part of West Hampstead, a little later. The scene is illuminated by glaring floodlight. One of the well-kept terraced houses has been gutted by a raging fire, and it and its neighbouring houses are cordoned off. Firemen are working on securing the site with heavy machinery. There is still a haze of smoke in the air, but the fire is already extinguished. There is a fairly strong police presence, too, and some onlookers are loitering outside the perimeter of the crime scene, but there are no blue lights flashing. The catastrophe isn't all that recent and already under control._

 _A cab comes driving up and halts. Sherlock and John get out._

 _They're let through into the cordoned-off area by a uniformed constable as a matter of course. By the iron railing separating the burned-out house's front yard from the street, they're met by Greg Lestrade._

SHERLOCK _(looking straight over Lestrade's head, at the burned-out house):_ Alright, what've you got?

 _Lestrade nods hello to John, then half-turns back towards the site of the fire._

LESTRADE: Haven't been in there yet, but we're only waiting for the all-clear. _(He gestures at the forensics team that's already hovering in the background.)_ Seems the people who lived here had a built-in sauna installed in their basement. The firemen say it looks like they left the heater on too long, because the fire seems to have started there and then spread out.

JOHN: What idiots would leave the sauna oven on and not notice until the whole house was on fire?

LESTRADE: Dead idiots. They found two bodies down there, right in the sauna itself. A man and a woman. That's why _we're_ here.

JOHN: Sounds like a freak accident.

LESTRADE: I know.

 _Sherlock, who has been scanning the scene with his eyes all this time, now refocuses on Lestrade._

SHERLOCK: Why am I being requested to look into a freak accident?

LESTRADE: Because it stops looking like an accident when you find people dead in a sauna with their clothes on and the door blocked from the outside.

 _John grimaces._

SHERLOCK: Have they been identified?

LESTRADE: We'll have to wait for dental records or DNA to be sure. I'm told they're not a pretty sight. But it seems likely that they're the tenants of the house. _(He consults his notebook.)_ A middle-aged Swedish couple. The man's a professional football coach. Used to play for Sweden when he was younger. Their name's Hedlund. David and Sibylla.

 _Silence. Then John's head suddenly snaps towards Sherlock, his eyes wide._

JOHN _(aghast):_ Jesus.

 _The fireman in command of the operation, dressed in his heavy protective suit and helmet and carrying a SCBA mask in his hand, comes over to them and addresses Lestrade._

FIREMAN: Sorry, Detective Inspector. I can't let you fellows in just yet. It'll be at least an hour yet til we've got the basement secured so it won't fall on your heads. It's still too full of smoke for you to go in without masks, either.

LESTRADE _(resigning himself to a long night):_ Alright. Give me a shout when you're ready. _(To Sherlock and John, apologetically)_ Sorry about that. He'd said earlier that -

SHERLOCK _(generously):_ Well, never mind. Come to Baker Street tomorrow morning and tell us what you've got.

 _He turns and walks away. John exchanges a surprised look with Lestrade, but Lestrade only shrugs. John nods goodbye and follows Sherlock. He catches up with him after a few steps._

JOHN: Don't tell me you didn't notice.

SHERLOCK _(walking on):_ Notice what?

 _John digs the concert programme out of the pocket of his jacket and holds it up._

JOHN: "The day of wrath, that day that will dissolve the world in ashes, as David and the Sybil foretold." The first verse of the "Dies Irae" sequence from the Requiem.

SHERLOCK _(dismissively):_ What's an eighteenth century funeral mass got to do with a twenty-first century crime?

JOHN: That's what I'd like to know. Those names, Sherlock. What kind of sick coincidence is that?

SHERLOCK: What's in a name? _(They duck under the police tape and continue down the pavement.)_ I wouldn't have taken you for a superstitious man, John.

JOHN: It's not superstition, it's a fact! Don't _you_ find it damn odd to come out of Mozart's Requiem to find two people called David and Sybilla reduced to ashes? On Ash Wednesday, too? Don't tell me _that's_ Mycroft's sense of humour.

SHERLOCK: None of this has anything to do with Mycroft, John.

JOHN _(stopping in his tracks):_ What?

SHERLOCK _(impatiently):_ Use your eyes. Look at the tickets, and look properly for once.

 _John takes the concert tickets back out of the pocket of his jacket where he's stored them. They halt under a streetlamp to look._

SHERLOCK: They're not subscription tickets. They were bought individually, only today, from one of those box office stalls in the West End. See the little numbers there, in the bottom left corner? _(He points with a gloved finger.)_ Date and time of purchase.

JOHN _(peering at the printed numerals):_ 5:48 this afternoon?

SHERLOCK: Exactly. Besides, they were for seats in the first row. As you noticed yourself, in a concert featuring a symphonic orchestra playing with maximum symphonic vehemence ninety percent of the time, placing someone there equals an acoustic assault. You may think what you like of Mycroft otherwise, but he's definitely above suspicion in that department.

JOHN _(incredulously):_ So - so you're saying that you knew all along that those tickets _didn't_ come from Mycroft?

SHERLOCK: As soon as I saw them, yes.

JOHN _(with great indignation):_ But you still sat through that whole concert, cool as a cucumber, while mere miles away two people were burnt horribly to death in their own basement?

SHERLOCK _(offended):_ Excuse me? I know how to use my eyes, John, but I'm not clairvoyant. How was I to know that -

JOHN _(still angrily):_ \- that the tickets were a ruse to keep you from stopping a murderer? No, nothing suspicious about them at all, was there? Just a little hocus-pocus with a masked stranger knocking on our door, and -

SHERLOCK _(crossing his arms belligerently):_ Don't tell me you weren't intrigued by that, too!

JOHN _(bitterly):_ If you'd believed that, you wouldn't have kept me in the dark, to make sure I'd come along quietly. You just wanted some private fun with that little puzzle, didn't you? Is that why you couldn't keep your eyes on the performance? You thought someone had sent you to the concert on purpose because something _intriguing_ was going to happen at the church itself?

SHERLOCK _(defensively):_ It was the most likely explanation!

JOHN: Well, you were wrong then, weren't you? And now Greg's got a double murder on his hands, and -

SHERLOCK _(cutting him off, with cold dignity):_ You go on ahead, John. I need to go back. There's something I forgot. I'll see you in the morning.

 _He turns on his heel and walks back towards the scene of the fire. John shakes his head after him, then squares his shoulders and walks off with firm steps into the direction of the main road, not looking back._

 _Sherlock, meanwhile, has returned to the crime scene. There's a fire engine parked at the edge of the cordoned-off area, and two or three firemen are sitting on the back steps, facing away from the ruin of the house, taking a short break from their duties. They're sipping from water bottles and talking in an undertone. One of them has taken off his heavy protective jacket, his helmet and his breathing mask, and has hung them on the iron railing in front of the adjoining house, a little aside from where they're sitting. Sherlock comes sneaking up to the equipment and lifts it soundlessly from its impromptu hooks, while the firemen are looking the other way._

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 **Author's Note:**

I really must apologise to you all, but this will be the last chapter of our story that I'm posting here on the site. Translating the multi-media content and the interactive aspect into plain narrative just about worked for this chapter, but there are chapters coming up in which it won't work at all. Besides, it seems a shame to strip the story of what - in our eyes - makes it really special.

I really don't want to lure anyone away from your preferred archive - but just for this one story, may I ask you all to come over to AO3 (Archive Of Our Own) and continue reading it there instead of here? You'll find me there under the name Jolie_Black, and the story under the same title as here. My co-author RubraSaetaFictor and I are hoping to keep you all well entertained over the summer, and we'd hate to lose a single reader just because this site doesn't do images/audio and doesn't have a comments section...

If you don't have an AO3 account, no problem. You don't need to be logged in to read and comment. The subscription/follow feature is available only to registered users, but I'd be happy to notify you of any new updates to the story via a PM on this site, too. Just drop me a line if you want me to.

I'm marking this fragment as complete even though it isn't, just so nobody keeps waiting for updates that aren't coming.

Hope to see you all on AO3! The story continues in Chapter 4, over there. :-)


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